You mean the broadcast-grade ones? With the air bearings? Whoa.
They made a beautiful sound when they were running in sync, as I recall. That high-pitch vertical-retrace frequency, or some integer fraction of it.
I used to be able to hear that when I was a kid. Now I couldn't, but no one else can either. It's gone.
I used to build gizmos for a private investigator back when I was a kid.
He used Super 8 cameras that I modified with an intervalometer and shot a lot of old U-Matic and reel-to-reel video... ancient gear!
I mostly built sound-controlled switches, shutter intervalometers, telephone dial-pulse recorders, transmitters and time-stamp devices for him.
The air bearing noise I will never forget.
There was one of each but in different parts of the building.